Withdrawal bleeding that occurs during the placebo period of the traditional OCP regimen is unnecessary and unwanted, and contributes to substantial method discontinuation rates. In U.S. women this contributes to one of the highest unwanted pregnancy rates in the world. In this proposal we will test the hypothesis that a long-term (6 month) continuous combined oral contraceptive pill (CCOCP) regimen (20 mug ethinyl estradiol/1 mg norethindrone acetate) will result in more profound endometrial and ovarian suppression than a traditional 21 day active pill/7 day placebo OCP regimen (21/70CP) with a randomized double blind trial. Currently CCOCP is commonly used by clinicians for a variety of indications, with little data of its safety and efficacy. As the clinical marker of endometrial and ovarian activity, we will be using number of bleeding days as the primary outcome in this study. We will secondarily monitor endometrial thickness and ovarian follicle formation by ultrasound, endometrial histology by biopsy, ovarian steroid production by monthly serum and daily urinary measurements, and patient satisfaction by questionnaire. We believe that a reduction in days of bleeding that will occur on a CCOCP regimen will improve patient satisfaction and compliance with this contraceptive regimen. We theorize that a tong-term CCOCP regimen may more effectively suppress ovarian follicular development and endometrial growth, because there are fewer rebounds in hormone levels due to loss of suppression during placebo periods. This regimen may therefore provide both effective contraception (with greater leeway for skipped pills) as well as more effective treatment of multiple gynecological conditions such as dysmenorrhea, dysfunctional uterine bleeding, endometriosis, and peripheral androgen disorders such as acne and hirsutism, as well as a greater reduction in risk for endometrial and ovarian cancer. Therefore, the risks and benefits of a CCOCP regimen are an important women's health issue that warrant investigation.